Lift truck with lazy tong pusher



March 1954 w. H. THOMPSON LIFT TRUCK WITH LAZY TONG PUSHER INVENTOR.

TUBA/75 2 Sheets-Sheet l Original Filed July 8, .1948

WARRfN/i THOMPSON Patented Mar. 2, 1954 LIFT TRUCK WITH LAZY TONG PUSHERWarren H. Thompson,

to Towmotor corporation of Ohio Wicklifie, Ohio, assignor Corporation,Cleveland, Ohio, a

Continuation of application Serial No. 37,711,

July 8, 1948. This ap Serial No. 162,865

' 3 Claims.

This invention relates broadly to lift trucks and more specifically toimprovements in pushers for ejecting the work from the load-carryingplatform. This application is a continuation of my co-pendingapplication, Serial No. 37,711, filed July 8, 1948, for Lazy Tong Pusherfor Industrial Trucks, now forfeited.

One of the objects of the invention is to provide a pusher plateactuating mechanism which is designed to afford free access to thevehicle and avoid the hazard of injury to the operator by elimination ofsuch parts as customarily traverse the zone of his activity during theelevation of the load. To this end the invention contemplates a pair oflazy tongs nested, in their closed position, forward the steering columnand distensible the length of the forks. The lazy tongs are actuated bylinkage coupled with a hydraulic plication May 19, 1950,

ram which is carried by the elevating mechanism and likewise disposedforwardly of the driver.

Another object of the invention is to provide a coupling between thepusher and lazy tongs which will support the plate in normal relation tothe load-carrying platform throughout the actuation of the pusher.

Another object of the invention is to provide linkage for actuating thelazy tongs which effect the operation thereof with a minimum effort.

Other objects of the invention reside in the provision of a pusher whichis efiicient of operation, economic of manufacture, sturdy of structure,and adapted for interchangeable assembly on vehicles of variable sizeand design. 7

Other objects and advantages more or less ancillary to the foregoing,and the manner in which all the various objects are realized, willappear in the following description, which, considered in connectionwith the accompanying drawings, sets forththe preferred embodiment ofthe invention.

Referring to the drawings:

Fig. 1 is a side elevational view of the improved pusher in itsdistended position;

Fig. 2 is a similar View shown upon an enlarged scale with the lazytongs in their retracted position, certain of the parts in this viewbeing broken away and shown in section in the interest of clarity;

Fig. 3 is a front elevational view of a fragmentary portion of thepusher;

Fig. 4 is a vertical sectional view through the lazy tongs and.supporting frame therefor, the section being taken on a plane indicatedby the line 4-4 in Fig. 2; and,

Fig. 5 is a transverse sectional view through the lazy tongs guide railand carriage, the sec- 2 tion being taken on a plane indicated by theline 5-5 in Fig. 2.

Referring first toFig. l, the vehicle for which the improved pusher isdesigned may be of any conventional form, such, for example, as theIndustrial Truck disclosed in Letters Patent of the United States No.2,418,661, issued April 8, 1947, to Dwight M. Palm. The vehiclecomprises a frame Ill supported on dirigible wheels I I, a steering gearl2 therefor, a fixed mast l3 adjacent the front wheels, a reciprocableslide I4 therein, and a load-carrying platform or fork I5 carriedthereby. The vehicle further includes a hydraulic pump and liftcylinder, not shown, for elevating the slide, and a multi-valveoperating unit I 6 for the control of the lift cylinder and otheroperating mechanisms in the machine. The pusher is supported by acarriag I! which is mounted on the slide I4 and constructed for theretention of the fork I5. The carriage is formed with cross members I8having the ends thereof disposed beyond the plane of the side walls ofeach stanchion of the mast I3. The ends of the cross members retain theframes I9 that constitute the supporting elements for the hydraulicjacks, lazy tongs, and operating linkage therefor. The frames aredisposed in parallel relation with each other on opposite sides of thevehicle,.the inner ends thereof terminating forward the openingthat'forms the entry to the vehicle. In detail, each frame comprises atop rail 20, a bottom rail 2|, and an intermediate end member 22. Theend member is formed from a pair of channel irons mounted withthe centerwebs thereof in contiguous relation and with their flanged portionsnormal to the plane of the lazy tongs. The channels as thus arrangedform a track for guiding a carriage 23 which is pivotally connected tothe free end of the upper link of the lazy tongs 24. The lowerterminating link of the lazy tongs is pivoted in a bracket 25 welded orotherwise alfixed to the end member 22. The carriage comprises a pair ofplates 21 disposed adjacent the outer edges of the flanges andfabricated for the reception of stub axles 28 having rollers 29 thereonwhich engage the inner walls of the flanges.

The carriage is provided to facilitate the translation of the free linkof the lazy tongs and form a thrust bearing therefor during theactuation of the pusher. The end member 22 is provided with a lug 30subjacent the bracket 25 which is cross drilled for the pivotal supportof a hydraulic piston cylinder assembly 3 I. The cylinder is formed withports 32 in the opposed ends thereof to facilitate the reciprocativemovement of the piston when pressure fluid is admitted successivelythrough conduits 33 and 34 coupled with the ports and the control valveHi. The piston rod 35 is pivotally connected to the lower end of an arm36' mounted for pendulous movement on the rail 20 of the frame l9, andthis arm is connected in turn with a drag link 37 coupled with the firstsection of the lazy tongs. The lazy tongs are preferably constructedfrom a series of relatively heavy bars 38 pivotally connected at theirends and central portions to lighter cross bars 39 disposed on theopposed sides thereof. The upper forward link 49 of the lazy tongs ispivoted to a carriage ll similar in structure, and function to thecarriage 23. The carriage il is guided in a track 42 formed in thepusher plate t3, and the lower outer link 44 is pivoted in a bracket 45welded on the plate adjacent the lower end thereof.

Although the drag link as shown herein is connected to an extendedportion of each of the bars 39, it will be recognized that the link maybe connected to an elongated end of the companion bar 38 which isproportioned relative to the piston throw to provide the requisitedistention of the lazy tongs.

In operation, when the valve 16 is adjusted to admit pressure fluid tothe rearward portion of the cylinder the piston will be advanced andwill swing the arm 36 forwardly, thus eifectuating the distention of thelazy tongs and the removal of the work supported on the fork 15. Whenthe valve is reversed, pressure fluid will enter the forward end of thecylinder and effect the retraction of the lazy tongs. It will berecognized that the carriages 23 and M will maintain the pusher platenormal to the fork and parallel the medial axis of the lazy tongs as theangular relation of the cross links is changed during the operation ofthe pusher. It will be further noted that the structure of the linkageof the lazy tongs will accommodate the nesting thereof into such compactform that the assembly may be readily mounted on a vehicle intermediatethe elevating mechanism and the opening defining the entrance to thevehicle.

Although the foregoing description is necessarily of a detailedcharacter, in order that the invention may be completely set forth, itis to be understood that the specific terminology is not intended to berestrictive or confining, and that various rearrangements of parts andmodifications of detail may be resorted to without departing from thescope or spirit of the invention as herein claimed.

What is claimed is:

1. In a lift truck, a chassis, a mast mounted forwardly on said chassis,a carriage movable along said mast, supports extending rearwardly fromeach side of said carriage and straddling said mast, lazy tongs anchoredat one end to a rearward portion of said supports and joined at theirforward ends to a pusher plate, and motor means for extending andretracting said lazy tongs.

2. In a lift truck, a chassis, a mast mounted forwardly on said chassis,a carriage movable along said mast, a driver's compartment rearwardly ofsaid mast, supports extending rearwardly from each side of said carriageand straddling said mast, said supports stopping short of the forwardwall of said drivers compartment, lazy tongs anchored at one end to arearward portion of said supports and joined at their forward ends to apusher plate and motor means for extending and retracting said lazytongs.

3. In a lift truck embodying a chassis, a mast on the forward endthereof, a carriage movable vertically along said mast, a horizontalload-carrying platform extending forwardly from said carriage, and atruck body on said chassis having a drivers station formed therein, saiddrivers station being disposed rearwardly of said mast, a pusher fordischarging material on the loadcarrying platform comprising avertically disposed pusher plate forward of said carriage and above saidplatform, vertically disposed rails mounted for vertical movement withsaid carriage and disposed adjacent the forward end of said driver'sstation when the carriage is in its lowered position, multiple link lazytong assemblies pivotally connected at one end to said rails and at theother end to said pusher plate, a piston and cylinder assembly pivotallymounted at one end upon said rail subjacent one of said lazy tongassemblies, means pivotally connecting the other end of said piston andcylinder assembly to a link in said lazy tong assemblies, said lazy tongassemblies being disposed between said rail and the rear of saidplatform while in their retracted position and between said rail and theforward end of said platform while in their distended position, androller means on said lazy tong assemblies engaged with and verticallymovable upon said rail and said pusher plate for supporting the plate innormal relation to said platform.

WARREN H. THOMPSON.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,977,785 Wheelock Oct. 23, 1934 2,256,454 Bomar -2 Sept. 16,1941 2,412,155 Jessen Dec. 3, 1946 2,418,661 Palm Apr. 8, 1947 2,583,977Turner Jan. 29, 1952 FOREIGN PATENTS Number Country Date 474,968 GermanyApr. 17, 1929 323,812 Italy Jan. 9, 1935

